Exemplary embodiments of the present invention relate to a projection display device.
Related art document JP-UM-A-1-115778 discloses rear projection display device, in which the entire optical system is accommodated in the cabinet. FIG. 19 is a schematic showing the configuration of the rear projection display device disclosed in the related art. The projection display device shown in FIG. 19 has a projection device 200 including an enclosure and a projection lens, a folding mirror 201, a transmission screen 202, and a cabinet 203. The viewer watches an enlarged image on the transmission screen 202 from a direction opposite to the projection device 200.
Because the entire optical system is accommodated in the cabinet in the rear projection display device, a projection light will not be shielded by an individual or furniture. In addition, because contrast deterioration is small under normal interior illumination and the cabinet, which is relatively small, is set near the wall or at a corner of the room, the rear projection display device does not present a problem in the layout at the center of the room.
Incidentally, in order to obtain a large screen with the rear projection display device, either a projection distance needs to be extended or an angle of view of the projection lens needs to be widened. The former, however, has a problem that the cabinet is generally increased in size (in particular, in depth) and a larger setup space is needed. On the other hand, the latter has a problem that a larger number of lenses are needed to widen the angle of the projection lens, which increases the cost.
Further, because the projection device, the folding mirror, and the transmission screen are provided integrally in the cabinet, there is a problem that the transmission screen alone cannot be replaced with another transmission screen when such a need arises.